Communication apparatus and communication system

ABSTRACT

The present technique relates to a communication apparatus and a communication system allowing distribution of loads on a communication apparatus that manages Internet connection. A communication system according to an aspect of the present technique includes: a first communication apparatus included in a wireless LAN including a plurality of communication apparatuses functioning as gateways, the first communication apparatus including a communication control section configured to transmit, when the first communication apparatus is connected to an external network, a management frame including a parameter related to a capability of connecting to the external network, to another apparatus within the wireless LAN; and a second communication apparatus operating as the first communication apparatus and including a communication control section configured to receive the management frame transmitted from the first communication apparatus and transmit, to the first communication apparatus, connection request information representing a request for connection to the external network. The present technique can be applied to a communication apparatus for a wireless LAN.

TECHNICAL FIELD

The present technique relates to a communication apparatus and acommunication system, and in particular to a communication apparatus anda communication system enabled to distribute loads on a communicationapparatus that manages Internet connection.

BACKGROUND ART

A BSS (Basic Service Set) corresponding to a wireless LAN networkincludes one access point and clients located within a reachable rangeof radio waves from the access point.

PTL 1 discloses a technique for a network including an access point anda plurality of mobile routers, the technique involving automaticallyconstructing a mesh network on the basis of information related to apath from the access point to the Internet. Even in a case where amobile router is located in an area where radio waves from the accesspoint fail to reach the mobile router, the mobile router can access theaccess point via another mobile router to make Internet connectionwithout using a mobile network.

CITATION LIST Patent Literature [PTL 1]

Japanese Patent Laid-Open No. 2015-186162

SUMMARY Technical Problems

In the network as described above, all communication within the networkconcentrates on the single access point, and thus heavy loads areimposed on the access point. Additionally, in a case where any defectoccurs at the access point, communication apparatuses within the networkare precluded from connecting to the Internet.

In recent years, there has been an increase in the number ofcommunication apparatuses that can operate as access points such assmartphones equipped with a function referred to as tethering.

Even though a plurality of communication apparatuses that can operate asaccess points is present within the same wireless LAN network, only onecommunication apparatus operates as an access point. This representsineffective use of the functions of the communication apparatuses in thewhole system.

In light of these circumstances, an object of the present technique isto allow distribution of loads on a communication apparatus that managesInternet connection.

Solution to Problems

A communication apparatus according to a first aspect of the presenttechnique is included in a wireless LAN including a plurality ofcommunication apparatuses functioning as gateways and includes acommunication control section configured to transmit, when the subjectcommunication apparatus is connected to an external network, amanagement frame including a parameter related to a capability ofconnecting to the external network, to another apparatus within thewireless LAN.

A communication apparatus according to a second aspect of the presenttechnique includes a communication control section configured to receivea management frame transmitted from a predetermined apparatus connectedto an external network and included in a plurality of predeterminedapparatuses functioning as gateways for a wireless LAN, the managementframe including a parameter related to a capability of connecting to theexternal network, the communication control section transmitting, to anyone of the predetermined apparatuses, connection request informationrepresenting a request for connection to the external network.

In the first aspect of the present technique, in the wireless LANincluding the plurality of communication apparatuses functioning as thegateways, when the subject communication apparatus is connected to theexternal network, the management frame including the parameter relatedto the capability of connecting to the external network is transmittedto another apparatus within the wireless LAN.

In the second aspect of the present technique, the management frametransmitted from the predetermined apparatus connected to the externalnetwork and included in the plurality of predetermined apparatusesfunctioning as the gateways for the wireless LAN is received, themanagement frame including the parameter related to the capability ofconnecting to the external network, and the connection requestinformation representing the request for connection to the externalnetwork is transmitted to any one of the predetermined apparatuses.

Advantageous Effect of Invention

According to the present technique, loads on a communication apparatusthat manages Internet connection can be distributed.

Note that the effect described here is not necessarily restrictive andthat any of the effects described in the present disclosure may beproduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration example of a network inwhich functions of an AP are distributed.

FIG. 2 is a diagram illustrating an example of a flow of uplink data.

FIG. 3 is a diagram illustrating an example of a flow of downlink data.

FIG. 4 is a diagram illustrating an example of a positional relationamong communication apparatuses.

FIG. 5 is a sequence diagram illustrating a series of operations fordetermining roles of the communication apparatuses.

FIG. 6 is a diagram illustrating a configuration example of a RoleAvailable Information Element.

FIG. 7 is a diagram illustrating a configuration example of a RoleSeparate Information Element.

FIG. 8 is a diagram illustrating a configuration example of a network.

FIG. 9 is a sequence diagram illustrating a series of steps ofprocessing for selecting an IG used for Internet connection.

FIG. 10 is a diagram illustrating another configuration example of anetwork.

FIG. 11 is a sequence diagram illustrating a series of steps ofprocessing for data transmission using spatial multiplexingcommunication.

FIG. 12 is a diagram illustrating an example of adjustment oftransmission power for radio waves.

FIG. 13 is a diagram illustrating a configuration example of a GatewayAnnouncement frame.

FIG. 14 is a diagram illustrating a configuration example of a GatewayConnection Request frame.

FIG. 15 is a diagram illustrating a configuration example of a GatewayConnection Grant frame.

FIG. 16 is a diagram illustrating a configuration example of a GatewayDisconnection Request frame.

FIG. 17 is a diagram illustrating a configuration example of a GatewayDisconnection Grant frame.

FIG. 18 is a block diagram illustrating a configuration example of acommunication apparatus.

FIG. 19 is a block diagram illustrating a configuration example offunctions of a wireless communication module.

FIG. 20 is a flowchart illustrating processing executed by the IG.

FIG. 21 is a flowchart continued from FIG. 20 and illustrating theprocessing executed by the IG.

FIG. 22 is a flowchart illustrating processing executed by a Station.

FIG. 23 is a flowchart continued from FIG. 22 and illustrating theprocessing executed by the Station.

FIG. 24 is a diagram illustrating examples of parameters included inGateway Parameter.

FIG. 25 is a diagram illustrating examples of parameters included inGateway Attribute.

FIG. 26 is a diagram illustrating examples of parameters included inGateway Control.

FIG. 27 is a diagram illustrating an example of a flow of uplink data.

FIG. 28 is a diagram illustrating an example of a flow of downlink data.

FIG. 29 is a sequence diagram illustrating a series of steps ofprocessing for selecting an IG used for Internet connection.

FIG. 30 is a block diagram illustrating a configuration example of acomputer.

DESCRIPTION OF EMBODIMENT

An embodiment of the present technique will be described below. Thedescription will be provided in the following order.

1. Configuration Example of Wireless LAN Network with Functions ofAccess Point Distributed2. Example of Operations for Constructing Network with Functions of APDistributed

3. Example of Selection of IG 4. Example of Data Transmission UsingSpatial Multiplexing Communication 5. Example of Frame Format 6.Configuration Example of Communication Apparatus 7. Operations ofCommunication Apparatuses 8. Examples of Parameters

9. Example of Communication Relayed through AC

10. Modified Examples

<Configuration Example of Wireless LAN Network with Functions of AccessPoint Distributed>

FIG. 1 is a diagram illustrating a configuration example of a networkwith functions of an access point (AP) distributed according to anembodiment of the present technique.

Seven small circles illustrated in FIG. 1 each represent a communicationapparatus that has a communication function for a wireless LAN complyingwith predetermined standards of, for example, IEEE802.11. Dashed circlesrepresent reachable ranges of radio waves from the respectivecommunication apparatuses.

In the example in FIG. 1, a communication apparatus present near thecenter of the network operates as an Access Controller. Additionally, anupper left communication apparatus that can connect to an externalnetwork such as the Internet operates as an Internet Gateway 1, and alower right communication apparatus that can connect to the externalnetwork operates as an Internet Gateway 2.

In other words, in the network in FIG. 1, the communication apparatusoperating as an Access Controller takes responsibility for functions foraccess control in the network that are included in the functions ofknown APs and that include transmission of management frames. Themanagement frames transmitted by the Access Controller include a Beaconframe, an Action frame, a Management frame, and a Trigger frame.

The Beacon frame transmitted by the Access Controller includesinformation such as addresses of the respective communicationapparatuses included in the network. Signals transmitted by the AccessController control access of each communication apparatus to the AccessController or the Internet Gateway and identify the range of the BSS.

In the example in FIG. 1, the reachable range of radio waves from theAccess Controller, indicated by a circle #11, includes the InternetGateways 1 and 2 and Stations 1 to 4. The Stations 1 to 4, which arepresent within the reachable range of radio waves from the AccessController, operate as client communication apparatuses belonging to thenetwork managed by the Access Controller.

Additionally, the communication apparatuses operating as InternetGateways take responsibility for gateway functions for the externalnetwork that are included in the functions of known APs. The InternetGateways 1 and 2, for example, communicate with a server managed by aservice provider providing connection services for the Internet andcontrol transmission and reception of uplink data and downlink data.

The uplink data is, for example, data from the Stations to externalapparatuses on the Internet. The downlink data is data from the externalapparatuses on the Internet to the Stations.

In the example in FIG. 1, the reachable range of radio waves from theInternet Gateway 1, indicated by a circle #12, includes the Stations 1and 2 in addition to the Access Controller. Additionally, the reachablerange of radio waves from the Internet Gateway 2, indicated by a circle#13, includes the Stations 3 and 4 in addition to the Access Controller.Circles #21 to #24 represent the reachable ranges of radio waves fromthe Stations 1 to 4, respectively.

The Internet Gateway 1 manages Internet connection of the Station 1 andthe Station 2 which are present within the reachable range of radiowaves from the Internet Gateway 1. Communication of the Stations 1 and 2with external apparatuses on the Internet is performed via the InternetGateway 1.

Similarly, the Internet Gateway 2 manages Internet connection of theStation 3 and the Station 4 which are present within the reachable rangeof radio waves from the Internet Gateway 2. Communication of theStations 3 and 4 with external apparatuses on the Internet is performedvia the Internet Gateway 2.

As described above, in the network in FIG. 1, the communicationapparatuses different from the communication apparatus operating as anAccess Controller operate as Internet Gateways to enable the Stationsbelonging to the network to make Internet connection.

By sharing the functions of an AP among a plurality of communicationapparatuses, the network can be efficiently managed. The functions ofthe AP at least include the function for access control in the networkincluding transmission of the Beacon frame and the gateway function forthe external network.

Additionally, since the two communication apparatuses operate asInternet Gateways, communication within the network can be distributed.Three or more communication apparatuses may operate as InternetGateways.

It is sufficient that radio waves reach the ranges around the AccessController, and thus each communication apparatus can reducetransmission power for radio waves.

For example, even with the reduced transmission power of radio waves,the Access Controller can transmit signals such as for the Beacon frameinto the range including all the communication apparatuses and indicatedby the circle #11. In other words, a wireless LAN network can beconstructed within a narrow range around the Access Controller. Thereachable ranges of radio waves output by the respective communicationapparatuses included in the network in FIG. 1 are each a narrow rangeincluding the positions of adjacent communication apparatuses.

FIG. 2 is a diagram illustrating an example of a flow of uplink data.

Uplink data transmitted to an external apparatus by the Station 1 isreceived by the Internet Gateway 1 as indicated by blank arrow A1, andthe Internet Gateway 1 transmits the data to an external apparatuscorresponding to the destination. Uplink data transmitted to an externalapparatus by the Station 2 is received by the Internet Gateway 1 asindicated by blank arrow A2, and the Internet Gateway 1 transmits thedata to an external apparatus corresponding to the destination.

Similarly, uplink data transmitted to an external apparatus by theStation 3 is received by the Internet Gateway 2 as indicated by blankarrow A3, and the Internet Gateway 2 transmits the data to an externalapparatus corresponding to the destination. Uplink data transmitted toan external apparatus by the Station 4 is received by the InternetGateway 2 as indicated by blank arrow A4, and the Internet Gateway 2transmits the data to an external apparatus corresponding to thedestination.

FIG. 3 is a diagram illustrating an example of a flow of downlink data.

Downlink data for the Station 1 transmitted from an external apparatusand received by the Internet Gateway 1 is transmitted from the InternetGateway 1 to the Station 1 as indicated by blank arrow A11. Downlinkdata for the Station 2 transmitted from an external apparatus andreceived by the Internet Gateway 1 is transmitted from the InternetGateway 1 to the Station 2 as indicated by blank arrow A12.

Similarly, downlink data for the Station 3 transmitted from an externalapparatus and received by the Internet Gateway 2 is transmitted from theInternet Gateway 2 to the Station 3 as indicated by blank arrow A13.Downlink data for the Station 4 transmitted from an external apparatusand received by the Internet Gateway 2 is transmitted from the InternetGateway 2 to the Station 4 as indicated by blank arrow A14.

As described above, in the network in FIG. 1, Internet connections madeby the respective Stations are shared by the Internet Gateway 1 and theInternet Gateway 2.

The Access Controller is hereinafter referred to as AC and the InternetGateway is hereinafter referred to as IG, as appropriate.

Additionally, the Stations are each referred to as a Near Station or aFar station on the basis of the position of the Station with referenceto the Internet Gateway.

With the Internet Gateway 1 used as a reference, the Station 1 and theStation 2, which can communicate with the Internet Gateway 1, are NearStations. The Station 3 and the Station 4, which fail to communicatewith the Internet Gateway 1 but are present within the reachable rangeof radio waves from the AC, are Far Stations.

Additionally, with the Internet Gateway 2 used as a reference, theStation 3 and the Station 4, which can communicate with the InternetGateway 2, are Near Stations. The Station 1 and the Station 2, whichfail to communicate with the Internet Gateway 2 but are present withinthe reachable range of radio waves from the AC, are Far Stations.

Whether the Station operates as a Near Station or a Far Station isdetermined on the basis of a positional relation with the IG. Asdescribed below, even if any Far Station is prevented from utilizing thenearest Internet Gateway, the Far Station can connect to anotherInternet Gateway via the AC.

<Example of Operations for Constructing Network with Functions of APDistributed>

Now, operations of the network will be described which are intended toshare the functions of the AP among the plurality of communicationapparatuses as described above.

FIG. 4 is a diagram illustrating an example of the positional relationamong the communication apparatuses.

As illustrated in FIG. 4, in the description, STAs 1 to 4 representingthe Stations are assumed to be in a positional relation in which theStations are arranged in order from the left. Circles #51 to #54represent the reachable ranges of radio waves from the STAs 1 to 4,respectively.

In this example, each STA can communicate with the STA two STAs aheadbut fails to communicate with the STA further ahead. Specifically, theSTA 1 fails to communicate directly with the STA 4.

Each STA that can take responsibility for the functions of the AP canexchange information with surrounding STAs using, for example, theAction frame including information representing the functions for whichthe STA can take responsibility.

First, with reference to a sequence in FIG. 5, a series of operationswill be described that are intended to determine the role of each STA.Note that operations using the Action frame and the Beacon frame will bedescribed here for convenience but that, instead of these frames, theManagement frame may be used.

Here, the user is assumed to specify that the STA 2, which can operateas an AC, operates as an AC. Specifying the operation as an AC isperformed by, for example, operating the STA 2.

In a case where the operation as an AC is specified, the STA 2 transmitsthe Action frame including Role Available Information Element in stepS11. Role Available Information Element included in the Action frametransmitted by the STA 2 contains information indicating that the STA 2can operate as an AC.

The Action frame transmitted from the STA 2 is received by the STA 1 instep S1 and received by the STA 3 in step S21. Additionally, the Actionframe transmitted from the STA 2 is received by the STA 4 in step S31.

For example, the STA 1 and the STA 4, included in the STAs havingreceived the Action frame transmitted from the STA 2, are assumed to becommunication apparatuses that can connect to the Internet.

In this case, in step S2, the STA 1 transmits the Action frame includingthe Role Available Information Element. Role Available InformationElement included in the Action frame transmitted by the STA 1 containsinformation indicating that the STA 1 can operate as an IG.

The Action frame transmitted from the STA 1 is received by the STA 2 instep S12 and received by the STA 3 in step S22. The STA 1 and the STA 4are prevented from communicating directly with each other, and thus theAction frame transmitted from the STA 1 does not reach the STA 4.

On the other hand, in step S32, the STA 4 transmits the Action frameincluding Role Available Information Element. Role Available InformationElement included in the Action frame transmitted by the STA 4 containsinformation indicating that the STA 4 can operate as an IG.

The Action frame transmitted from the STA 4 is received by the STA 2 instep S13 and received by the STA 3 in step S23. The STA 1 and the STA 4are prevented from communicating directly with each other, and thus theAction frame transmitted from the STA 4 does not reach the STA 1.

In response to reception of the Action frame transmitted from the STA 1operating as an IG and the Action frame transmitted from the STA 4, theSTA 2 operating as an AC determines that a network with the functions ofthe AP distributed has been enabled to be operated.

In step S14, the STA 2 transmits the Beacon frame including RoleSeparate Information Element. Information representing the role of eachSTA is described in Role Separate Information Element included in theBeacon frame transmitted by the STA 2.

The STA 2, having transmitted the Beacon frame, performs in step S15configuration for operating as an AC.

The Beacon frame transmitted from the STA 2 is received by the STA 1 instep S3 and received by the STA 3 in step S24. Additionally, the Beaconframe transmitted from the STA 2 is received by the STA 4 in step S33.

The STA 1, having received in step S3 the Beacon frame transmitted fromSTA 2, performs in step S4 configuration for operating as an IG.

On the other hand, the STA 3, having received in step S24 the Beaconframe transmitted from the STA 2, performs in step S25 configuration foroperating as a Station. The STA 3 makes Internet connection using, forexample, the STA 1 operating as an IG.

Additionally, the STA 4, having received in step S33 the Beacon frametransmitted from STA 2, performs in step S34 configuration for operatingas an IG.

The above-described processing allows construction of a network in whichthe functions of the AP are distributed and which includes the two IGs.

FIG. 6 is a diagram illustrating a configuration example of RoleAvailable Information Element.

As illustrated in FIG. 6, Role Available Information Element includes IEType, Length, ESS ID, Own MAC Address, Controller Available, GatewayAvailable, and Intelligence Available.

IE Type indicates a format of an information element.

Length indicates an information length of the information element.

ESS ID indicates an identifier of an extended service set configured asneeded.

Own MAC Address indicates a MAC address of the communication apparatus.

Controller Available is a flag indicating whether or not thecommunication apparatus can operate as an AC. In the example in FIG. 5,a value indicating that the communication apparatus can operate as an ACis configured in Controller Available in Role Available InformationElement included in the Action frame transmitted by STA 2.

Gateway Available is a flag indicating whether or not the communicationapparatus can operate as an IG. In the example in FIG. 5, for example,Gateway Available in Role Available Information Element included in theAction frame transmitted by the STA 1 and the STA 4 is configured with avalue indicating that the communication apparatus can operate as an IG.

Intelligence Available is a flag indicating whether or not thecommunication apparatus can operate as an Intelligence Controller. Thecommunication apparatus used as an Intelligence Controller executesauthentication in the network and processing related to association withthe network. Specifically, the Intelligence Controller includes anauthentication function for the network and a function for processing anassociation request to the network, the functions being included in theknown functions of the AP.

As described above, the functions of the AP can be subdivided into morefunctions and some of the resultant functions of the AP can be sharedwith other communication apparatuses. In a case where the functions ofthe Intelligence Controller are shared, the STA that can operate as anIntelligence Controller transmits the Action frame including RoleAvailable Information Element configured with, as a value ofIntelligence Available, a value indicating that the STA can operate asan Intelligence Controller.

By using the Action frame including the information as illustrated inFIG. 6, each STA can transmit the functions for which the STA can takeresponsibility to the other STAs. Additionally, each STA can check, onthe basis of the Action frame transmitted from another STA, whether ornot any of the STAs in the network to which the subject STA belongstakes responsibility for each function of the AP.

FIG. 7 is a diagram illustrating a configuration example of RoleSeparate Information Element.

As illustrated in FIG. 7, Role Separate Information Element includes IEType, Length, SSID, ESS ID, Controller Address, Gateway Address 1,Gateway Address 2, and Intelligence Address. IE Type, Length, and ESS IDare respectively the same as IE Type, Length, and ESS ID described withreference to FIG. 6. SSID is a service set identifier configured asneeded.

Controller Address indicates an address of the STA operating as an AC.

Gateway Address 1 indicates an address of the STA operating as anInternet Gateway 1.

Gateway Address 2 indicates an address of the STA operating as anInternet Gateway 2.

Intelligence Address indicates an address of the STA operating as anIntelligence Controller.

In the example in FIG. 5, the address of the STA 2 itself is configuredin Controller Address of Role Separate Information Element included inthe Beacon frame transmitted by the STA 2, and the address of the STA 1is configured in Gateway Address 1 of Role Separate Information Element.The address of the STA 1 configured as Gateway Address 1 is, forexample, identified in the STA 2 on the basis of Own MAC Address of RoleAvailable Information Element in the Action frame transmitted by the STA1.

Additionally, the address of the STA 4 is configured in Gateway Address2 included in the Beacon frame transmitted by the STA 2. The address ofthe STA 4 configured as Gateway Address 2 is, for example, identified inthe STA 2 on the basis of Own MAC Address of Role Available InformationElement in the Action frame transmitted by the STA 4.

By using the Beacon frame including information as illustrated in FIG.7, the STA operating as an AC can transmit the address of each of theSTAs taking responsibility for the functions of the AP to the otherSTAs. Additionally, each of the STAs can identify, on the basis of theBeacon frame transmitted from the STA operating as an AC, the address ofeach of the other STAs taking responsibility for the functions of the APand belonging to the network to which the subject STA belongs.

One STA may be enabled to perform a plurality of functions of the AP. Inthis case, the address of the same STA is configured in two or more ofController Address, Gateway Address, and Intelligence Address.

Additionally, the addresses of three or more IGs may be enabled to bedescribed in Role Separate Information Element. Here, the addresses oftwo IGs are each described as Gateway Address. However, any number ofaddresses may each be configured as Gateway Address between ControllerAddress and Intelligence Address. In a configuration other than thisconfiguration, the number of apparatuses operating as IGs may beseparately described (not illustrated).

When the roles of the STAs are determined, the STAs transmit and receivethe Action frame including Role Available Information Element asmanagement information and the Beacon frame including Role SeparateInformation Element as management information as described above.

<Example of Selection of IG>

Now, description will be given of selection of the IG used for Internetconnection in a case where a plurality of IGs is present within thenetwork.

FIG. 8 is a diagram illustrating a configuration example of the network.

The network illustrated in FIG. 8 is similar to the network describedwith reference to FIG. 1 except for extended reachable ranges of radiowaves from the Internet Gateways 1 and 2 and the Stations 1 to 4operating while performing no transmission power control. Since notransmission power control is performed, transmitted signals reach theoutside of the desired range of the network.

In the example in FIG. 8, the reachable range of radio waves from theInternet Gateway 1, indicated by the circle #12, is extended to a rangeincluding the Stations 3 and 4. Additionally, the reachable range ofradio waves from the Internet Gateway 2, indicated by the circle #13, isextended to a range including the Stations 1 and 2.

Each of the Stations 1 and 2 can communicate with the Internet Gateway 1and the Internet Gateway 2. Each of the Stations 3 and 4 can similarlycommunicate with the Internet Gateway 1 and the Internet Gateway 2.

Each of the Stations selects, as an IG used for Internet connection, forexample, the IG located closest to the Station. For example, the IGlocated closest to the Stations 3 and 4 is the Internet Gateway 2.

With reference to a sequence in FIG. 9, a series of steps of processingwill be described in which the IG used for Internet connection isselected.

FIG. 9 illustrates processing of the Internet Gateways 1 and 2 andprocessing of the Stations 1 and 3. The Station 2 executes processingsimilar to the processing of the Station 1. The Station 4 executesprocessing similar to the processing of the Station 3. It is assumedthat only the Internet Gateway 1 is initially present as an IG and thatthe Internet Gateway 2 is subsequently configured.

In step S101, the Internet Gateway 1 transmits a Gateway Announcementframe indicating that the Internet Gateway 1 operates as an IG.

The Gateway Announcement frame may include the Action frame or include aManagement frame. In a case where the Internet Gateway 1 also functionsas an AC, the information in the Gateway Announcement frame may beincluded in the Beacon frame for transmission.

The Gateway Announcement frame transmitted from the Internet Gateway 1is received by the Station 1 in step S121 and received by the Station 3in step S131.

The Station 1 receives the Gateway Announcement frame, and in the caseof, for example, performing Internet connection and uploading User Datato an external apparatus, transmits to the Internet Gateway 1 a GatewayConnection Request frame including connection request informationrepresenting a request for Internet connection in step S122.

In step S102, the Internet Gateway 1 receives the Gateway ConnectionRequest frame transmitted from the Station 1.

In the case of accepting the request from the Station 1, the InternetGateway 1 returns a Gateway Connection Grant frame in step S103. TheGateway Connection Grant frame transmitted by the Internet Gateway 1 isgrant information representing grant of Internet connection via theInternet Gateway 1.

In step S123, the Station 1 receives the Gateway Connection Grant frametransmitted from the Internet Gateway 1. This enables the Station 1 toconnect to the Internet via the Internet Gateway 1 to communicate withan external apparatus.

For example, uplink User Data is transmitted from the Station 1 to theInternet Gateway 1 as indicated by blank arrow A51 and is transmittedvia the Internet Gateway 1 to an external apparatus as indicated byblank arrow A52. An ACK representing receipt acknowledgement is returnedfrom the Internet Gateway 1 to the Station 1 as indicated by arrow A53.

The Station 3, having received the Gateway Announcement frame from theInternet Gateway 1, executes similar processing.

Specifically, in step S132, the Station 3 transmits to the InternetGateway 1 the Gateway Connection Request frame requesting Internetconnection.

In step S104, the Internet Gateway 1 receives the Gateway ConnectionRequest frame transmitted from the Station 3.

In the case of accepting the request from the Station 3, the InternetGateway 1 returns the Gateway Connection Grant frame in step S105.

In step S133, the Station 3 receives the Gateway Connection Grant frametransmitted from the Internet Gateway 1. This enables the Station 3 toconnect to the Internet via the Internet Gateway 1 to communicate withan external apparatus.

Uplink User Data is transmitted from the Station 3 to the InternetGateway 1 as indicated by blank arrow A61 and is transmitted via theInternet Gateway 1 to the external apparatus as indicated by blank arrowA62. The ACK representing receipt acknowledgement is returned from theInternet Gateway 1 to the Station 3 as indicated by arrow A63. In thismanner, the Station 3 located away from the Internet Gateway 1 cancommunicate with the Internet Gateway 1 unless transmission power isreduced.

Here, it is assumed that the processing described with respect to FIG. 5is executed to configure the Internet Gateway 2 in the network.

In step S151, the Internet Gateway 2 transmits the Gateway Announcementframe indicating that the Internet Gateway 2 operates as an IG.

The Gateway Announcement frame transmitted from the Internet Gateway 2is received by the Station 1 in step S124 and received by Station 3 instep S134.

The Station 1, having received the Gateway Announcement frame, selectsmaintenance of the Internet connection using the Internet Gateway 1. Thedetermination in this case is made, for example, on the basis ofparameters included in the Gateway Announcement frame or on the basis ofa radio wave reception status.

Here, for example, in a case where the Internet Gateway 1 has a higherradio wave reception intensity than the Internet Gateway 2, maintenanceof the Internet connection using the Internet Gateway 1 is selected. TheInternet connection of the Station 1 remains active via the InternetGateway 1.

On the other hand, the Station 3, having received the GatewayAnnouncement frame, selects making of Internet connection using theInternet Gateway 2. The determination in this case is also made, forexample, on the basis of the parameters included in the GatewayAnnouncement frame or on the basis of the radio wave reception status.

For example, in a case where the Internet Gateway 2 has a higher radiowave reception intensity than the Internet Gateway 1, the InternetGateway 2 is determined to be more suitable, and the use of the InternetGateway 2 instead of the Internet Gateway 1 is selected.

In step S135, the Station 3 transmits to the Internet Gateway 1operating as an existing IG a Gateway Disconnection Request frameincluding cancel request information representing a request forcancellation of the Internet connection.

Additionally, in step S136, the Station 3 transmits to the InternetGateway 2 the Gateway Connection Request frame requesting Internetconnection.

In step S106, the Internet Gateway 1 receives the Gateway DisconnectionRequest frame transmitted from the Station 3.

In the case of accepting the request from the Station 3, the InternetGateway 1 returns a Gateway Disconnection Grant frame in step S107. TheGateway Disconnection Grant frame transmitted by the Internet Gateway 1is grant information representing grant of cancellation of Internetconnection via the Internet Gateway 1.

In step S137, the Station 3 receives the Gateway Disconnection Grantframe transmitted from the Internet Gateway 1. This disables the Station3 from connecting to the Internet via the Internet Gateway 1.

On the other hand, in step S152, the Internet Gateway 2 receives theGateway Connection Request frame transmitted from the Station 3.

In the case of accepting the request from the Station 3, the InternetGateway 2 returns the Gateway Connection Grant frame in step S153.

In step S138, the Station 3 receives the Gateway Connection Grant frametransmitted from the Internet Gateway 2. This enables the Station 3 toconnect to the Internet via the Internet Gateway 2 to communicate withan external apparatus.

Uplink User Data is transmitted from the Station 3 to the InternetGateway 2 as indicated by blank arrow A71 and is transmitted via theInternet Gateway 2 to the external apparatus as indicated by blank arrowA72. The ACK representing receipt acknowledgement is returned from theInternet Gateway 2 to the Station 3 as indicated by arrow A73.

As described above, in the network in which the plurality of IGs ispresent, each Station can select, for example, the closest IG as an IGsuitable for the Station and establish Internet connection via theselected IG. Additionally, even in a case where any IG has beenselected, each Station can switch from the selected existing IG toanother IG and make Internet connection to the other IG.

In a case where a plurality of IGs is present within the network,Internet connection is made using the closest IG to allow a reduction intransmission power for radio waves between each Station and the IG.

For example, processing illustrated in FIG. 9 is executed to enable theStations 1 and 2 in FIG. 8 to reduce the transmission power for radiowaves to allow the radio waves to reach the range including the AccessController and the Internet Gateway 1. Further, the Stations 3 and 4 inFIG. 8 are enabled to reduce the transmission power for radio waves toallow the radio waves to reach the range including the Access Controllerand the Internet Gateway 2.

The Internet Gateway 1 can reduce the transmission power for radio wavesto allow the radio waves to reach the range including the AccessController and the Stations 1 and 2 which make Internet connectionsusing the Internet Gateway 1. The Internet Gateway 2 can reduce thetransmission power for radio waves to allow the radio waves to reach therange including the Access Controller and the Stations 3 and 4 whichmake Internet connections using the Internet Gateway 2.

The Stations 1 to 4 and the Internet Gateways 1 and 2 thus reduce thetransmission power for radio waves, contributing to construction of anetwork in which the reachable range of radio waves from each apparatusis as described with reference to FIG. 1.

<Example of Data Transmission Using Spatial Multiplexing Communication>

With a plurality of IGs present within the network, data transmissionmay be performed using spatial multiplexing communication.

FIG. 10 is a diagram illustrating another configuration example of thenetwork.

As illustrated in FIG. 10, a positional relation is assumed in which theInternet Gateway 1, the Station 1, the Station 2, the and the InternetGateway 2 are arranged in this order from the left. The AC is present ata predetermined position within the network. Circles #61 to #64respectively represent the reachable ranges of radio waves from theInternet Gateway 1, the Station 1, the Station 2, and the InternetGateway 2.

In this example as well, each STA can communicate directly with the STAtwo STAs ahead but fails to communicate with the STAs further ahead.Specifically, the Internet Gateway 1 fails to communicate directly withthe Internet Gateway 2.

With reference to a sequence in FIG. 11, a series of steps of processingwill be described in which data transmission based on spatialmultiplexing communication is performed between each Station and theclosest IG.

In step S201, the Internet Gateway 1 transmits the Gateway Announcementframe indicating that the Internet Gateway 1 operates as an IG.

The Gateway Announcement frame transmitted from the Internet Gateway 1is received by the Station 1 in step S211 and received by Station 2 instep S221.

In step S231, the Internet Gateway 2 transmits the Gateway Announcementframe indicating that the Internet Gateway 2 operates as an IG.

The Gateway Announcement frame transmitted from the Internet Gateway 2is received by the Station 1 in step S212 and received by Station 2 instep S222.

The Station 1, having received the Gateway Announcement frame from boththe Internet Gateway 1 and the Internet Gateway 2, selects the InternetGateway 1 which is estimated to be the closest IG on the basis of aradio wave intensity and the like.

In step S213, the Station 1 transmits to the Internet Gateway 1 theGateway Connection Request frame requesting Internet connection.

In step S202, the Internet Gateway 1 receives the Gateway ConnectionRequest frame transmitted from the Station 1.

In the case of accepting the request from the Station 1, the InternetGateway 1 returns the Gateway Connection Grant frame in step S203.

In step S214, the Station 1 receives the Gateway Connection Grant frametransmitted from the Internet Gateway 1. This enables the Station 1 tobe connected to the Internet via the Internet Gateway 1 to communicatewith an external apparatus.

On the other hand, the Station 2, having received the GatewayAnnouncement frame from both the Internet Gateway 1 and the InternetGateway 2, selects the Internet Gateway 2 which is estimated to be theclosest IG on the basis of a received radio wave intensity and the like.

In step S223, the Station 2 transmits to the Internet Gateway 2 theGateway Connection Request frame requesting Internet connection.

In step S232, the Internet Gateway 2 receives the Gateway ConnectionRequest frame transmitted from the Station 2.

In the case of accepting the request from the Station 2, the InternetGateway 2, returns the Gateway Connection Grant frame in step S233.

In step S224, the Station 2 receives the Gateway Connection Grant frametransmitted from the Internet Gateway 2. This enables the Station 2 tobe connected to the Internet via the Internet Gateway 2 to communicatewith an external apparatus.

Here, for communication between the Internet Gateway 1 and the Station 1and communication between the Internet Gateway 2 and the Station 2, thetransmission power is adjusted to provide a minimum necessary reachablerange of radio waves, User Data is transmitted as indicated by blankarrows A102 and A112, and the ACK is returned as indicated by arrowsA103 and A113.

FIG. 12 is a diagram illustrating an example of adjustment of thetransmission power for radio waves.

As indicated by circle #61, the reachable range of radio waves from theInternet Gateway 1 is adjusted to include the Station 1 and the AC.

As indicated by circle #62, the reachable range of radio waves from theStation 1 is adjusted to include at least the Internet Gateway 1 and theAC.

As indicated by circle #63, the reachable range of radio waves from theStation 2 is adjusted to include at least the Internet Gateway 2 and theAC.

As indicated by circle #64, the reachable range of radio waves from theInternet Gateway 2 is adjusted to include the Station 2 and the AC.

In a case where the reachable range of radio waves from each STA isadjusted as illustrated in FIG. 12, downlink data transmitted by theInternet Gateway 1 and destined for the Station 1 does not reach theStation 2. Additionally, downlink data transmitted by the InternetGateway 2 and destined for the Station 2 does not reach the Station 1.

Transmission of downlink data to the Station 1 by the Internet Gateway 1and transmission of downlink data from the Internet Gateway 2 to theStation 2 can be performed, for example, with timings for thetransmissions overlapping. Additionally, reception of downlink data bythe Station 1 and reception of downlink data by the Station 2 can beperformed, for example, with timings for the receptions overlapping.

Specifically, as indicated by blank arrow A101 in FIG. 11, downlink UserData destined for the Station 1, which has been transmitted by anexternal apparatus via the Internet and received at the Internet Gateway1 via the Internet, is transmitted from the Internet Gateway 1 to theStation 1 as indicated by blank arrow A102.

Additionally, as indicated by blank arrow A111, downlink User Datadestined for the Station 2, which has been transmitted by an externalapparatus via the Internet and received at the Internet Gateway 2 viathe Internet, is transmitted from the Internet Gateway 2 to the Station2 as indicated by blank arrow A112.

Transmission of User Data from the Internet Gateway 1 to the Station 1illustrated by blank arrow A102 and transmission of User Data from theInternet Gateway 2 to the Station 2 illustrated by blank arrow A112 are,for example, timed to take place simultaneously.

Return of the ACK from the Station 1 to the Internet Gateway 1illustrated by arrow A103 and return of the ACK from the Station 2 tothe Internet Gateway 2 illustrated by arrow A113 are, for example, timedto take place simultaneously.

The transmission timing for User Data and the return timing for the ACKmay be specified by information included in a Trigger frame transmittedby the AC.

In a network in which a plurality of IGs is present, each Stationselects the closest IG, and the IG and the Station optimize thetransmission power for radio waves, enabling spatial multiplexingcommunication. This enables utilization efficiency of transmission pathsto be improved.

<Example of Frame Format>

Now, a configuration of each of the frames used for the above-describedprocessing will be described.

FIG. 13 is a diagram illustrating a configuration example of the GatewayAnnouncement frame.

As described above, the Gateway Announcement frame includes the Actionframe or the Management frame. The Gateway Announcement frame istransmitted from the Internet Gateway to neighboring Stations. In a casewhere one STA takes responsibility for the functions of the IG and theAC, the information in the Gateway Announcement frame is included in theBeacon frame for transmission.

As illustrated in FIG. 13, the Gateway Announcement frame includes FrameControl, Duration, Broadcast Address, Gateway Address, BSS ID, SequenceControl, ESS ID, Gateway Parameter, Gateway Attribute, and GatewayControl. An FCS including an error detection code is added to a tail endof each of these pieces of information to form the Gateway Announcementframe.

Frame Control represents a type of the frame.

Duration represents a duration of the frame.

Broadcast Address represents an address of a destination of the GatewayAnnouncement frame.

Gateway Address represents an address of a source of the GatewayAnnouncement frame.

BSS ID is an identifier of the BSS to which the communication apparatusbelongs.

Sequence Control represents a sequence number or the like.

ESS ID is an identifier of an ESS.

Gateway Parameter includes parameters related to Internet connectioncapabilities (specifications). Gateway Parameter includes parametersincluded in the parameters related to the Internet connectioncapabilities and varying with state.

Gateway Attribute also includes parameters related to the Internetconnection capabilities. Gateway Attribute includes invariableparameters corresponding to attributes of the IG, the invariableparameters being included in the parameters related to the Internetconnection capabilities.

Gateway Control is information related to control of the IG. GatewayControl includes, for example, parameters configured by a user andparameters configured in accordance with instructions from apredetermined apparatus on the network.

Gateway Parameter, Gateway Attribute, and Gateway Control will bedescribed below in detail.

FIG. 14 is a diagram illustrating a configuration example of the GatewayConnection Request frame.

The Gateway Connection Request frame includes the Action frame or theManagement frame. The Gateway Connection Request frame is transmittedfrom the Station to the IG to which Internet connection is requested.

As illustrated in FIG. 14, the Gateway Connection Request frame includesFrame Control, Duration, Gateway Address, Transmit Address, BSS ID,Sequence Control, and Another Gateway Address. An FCS is added to a tailend of each of these pieces of information to form the GatewayConnection Request frame.

Frame Control represents a type of the frame.

Duration represents a duration of the frame.

Gateway Address represents an address of a destination of the GatewayConnection Request frame. Gateway Address specifies the IG requestingInternet connection.

Transmit Address represents an address of a source of the GatewayConnection Request frame. Transmit Address represents the Stationrequesting Internet connection.

BSS ID is an identifier of the BSS to which the communication apparatusbelongs.

Sequence Control represents a sequence number or the like.

Another Gateway Address is used in a case where a communicationapparatus is present that operates as an IG and that is other than thecommunication apparatus operating as the destination of the GatewayConnection Request frame, and Another Gateway Address describes theaddress of the former communication apparatus. In a case where aplurality of communication apparatuses is present that operates as IGsand that is other than the communication apparatus operating as thedestination of the Gateway Connection Request frame, Another GatewayAddress describes each of the addresses of these communicationapparatuses.

FIG. 15 is a diagram illustrating a configuration example of the GatewayConnection Grant frame.

The Gateway Connection Grant frame includes the Action frame or theManagement frame. The Gateway Connection Grant frame is transmitted fromthe IG to the communication apparatus requesting Internet connection ina case where the Internet connection is accepted.

As illustrated in FIG. 15, the Gateway Connection Grant frame includesFrame Control, Duration, Target Address, Gateway Address, BSS ID,Sequence Control, and Another Gateway Address. An FCS is added to a tailend of each of these pieces of information to form the GatewayConnection Grant frame.

Frame Control represents a type of the frame.

Duration represents a duration of the frame.

Target Address represents an address of a destination of the GatewayConnection Grant frame. Target Address specifies the Station for whichInternet connection is accepted.

Gateway Address represents an address of a source of the GatewayConnection Grant frame. Gateway Address represents the IG havingaccepted the Internet connection.

BSS ID is an identifier of the BSS to which the communication apparatusbelongs.

Sequence Control represents a sequence number or the like.

Another Gateway Address is used in a case where a communicationapparatus is present that operates as an IG and that is other than thecommunication apparatus operating as the source of the GatewayConnection Grant frame, and Another Gateway Address describes theaddress of the former communication apparatus. In a case where aplurality of communication apparatuses is present that operates as IGsand that is other than the communication apparatus operating as thesource of the Gateway Connection Grant frame, Another Gateway Addressdescribes each of the addresses of these communication apparatuses.

FIG. 16 is a diagram illustrating a configuration example of the GatewayDisconnection Request frame.

The Gateway Disconnection Request frame includes the Action frame or theManagement frame. The Gateway Disconnection Request frame is transmittedfrom the Station to the IG to which cancellation of Internet connectionis requested.

As illustrated in FIG. 16, the Gateway Disconnection Request frameincludes Frame Control, Duration, Old Gateway Address, Transmit Address,BSS ID, Sequence Control, and New Gateway Address. An FCS is added to atail end of each of these pieces of information to form the GatewayDisconnection Request frame.

Frame Control represents a type of the frame.

Duration represents a duration of the frame.

Old Gateway Address represents an address of a destination of theGateway Disconnection Request frame. Old Gateway Address specifies theIG to which cancellation of Internet connection is requested.

Transmit Address represents an address of a source of the GatewayDisconnection Request frame. Transmit Address represents the Stationrequesting cancellation of Internet connection.

BSS ID is an identifier of the BSS to which the communication apparatusbelongs.

Sequence Control represents a sequence number or the like.

New Gateway Address represents an address of the IG as a new connectiondestination of the Internet connection.

FIG. 17 is a diagram illustrating a configuration example of the GatewayDisconnection Grant frame.

The Gateway Disconnection Grant frame includes the Action frame or theManagement frame. The Gateway Disconnection Grant frame is transmitted,in a case where cancellation of Internet connection is accepted, fromthe IG to the communication apparatus requesting the cancellation of theInternet connection.

As illustrated in FIG. 17, the Gateway Disconnection Grant frameincludes Frame Control, Duration, Target Address, Old Gateway Address,BSS ID, Sequence Control, and New Gateway Address. An FCS is added to atail end of each of these pieces of information to form the GatewayDisconnection Grant frame.

Frame Control represents a type of the frame.

Duration represents a duration of the frame.

Target Address represents an address of a destination of the GatewayDisconnection Grant frame. Target Address specifies the Station forwhich cancellation of Internet connection is accepted.

Old Gateway Address represents an address of a source of the GatewayDisconnection Grant frame. Old Gateway Address represents the IG itselfhaving accepted the cancellation of the Internet connection.

BSS ID is an identifier of the BSS to which the communication apparatusbelongs.

Sequence Control represents a sequence number or the like.

New Gateway Address represents an address of the IG as a new destinationof the Internet connection specified by the Station requesting thecancellation of the Internet connection.

<Configuration Example of Communication Apparatus>

FIG. 18 is a block diagram illustrating a configuration example of thecommunication apparatus.

A communication apparatus 11 illustrated in FIG. 18 is an STA operatingas an AC, an IG, a Station, or the like.

The communication apparatus 11 includes, for example, an Internetconnection module 21, an information input module 22, an equipmentcontrol section 23, an information output module 24, and a wirelesscommunication module 25. The components illustrated in FIG. 18 can beomitted as appropriate according to the functions for which eachcommunication apparatus 11 takes responsibility.

The Internet connection module 21 functions as a communication modem forconnection to the Internet in a case where the communication apparatus11 operates as an IG. Specifically, the Internet connection module 21outputs to the equipment control section 23 data received via theInternet and transmits data fed from the equipment control section 23 toa destination apparatus via the Internet.

The Internet connection made by the Internet connection module 21 isachieved via a wired communication network or a wireless communicationnetwork.

The information input module 22 detects an operation by the user andoutputs to the equipment control section 23 information representing thecontents of the operation by the user. For example, in a case where abutton, a keyboard, a touch panel, or the like provided on a housing ofthe communication apparatus 11 is operated, the information input module22 outputs to the equipment control section 23 a signal corresponding tothe operation performed by the user.

The equipment control section 23 includes a CPU (Central ProcessingUnit), a ROM (Read Only Memory), a RAM (Random Access Memory), and thelike. The equipment control section 23 uses the CPU to execute apredetermined program and controls operations of the communicationapparatus 11 as a whole in accordance with, for example, signals fedfrom the information input module 22.

For example, the equipment control section 23 outputs to the wirelesscommunication module 25 downlink data fed from the Internet connectionmodule 21 and causes the wireless communication module 25 to transmitthe downlink data to the destination communication apparatus.Additionally, the equipment control section 23 acquires from thewireless communication module 25 uplink data transmitted from thecommunication apparatus belonging to the network and received by thewireless communication module 25 and outputs the uplink data to theInternet connection module 21. The equipment control section 23 causesthe information output module 24 to output predetermined information asappropriate.

The information output module 24 includes a display section including aliquid crystal panel, a speaker, and an LED (Light Emitting Diode). Onthe basis of the information fed from the equipment control section 23,the information output module 24 outputs various types of informationsuch as information representing an operating status of thecommunication apparatus 11 and information obtained via the Internet topresent the information to the user.

The wireless communication module 25 is a module for a wireless LANcomplying with predetermined standards. The wireless communicationmodule 25 is configured, for example, as an LSI chip.

The wireless communication module 25 transmits data fed from theequipment control section 23 to another apparatus using a frame in apredetermined format, receives a signal transmitted from anotherapparatus, and outputs to the equipment control section 23 dataextracted from the received signal.

FIG. 19 is a block diagram illustrating a configuration example offunctions of the wireless communication module 25.

As illustrated in FIG. 19, the wireless communication module 25 includesan input/output section 51, a communication control section 52, and abaseband processing section 53.

The input/output section 51 includes an interface section 101, atransmission buffer 102, a network management section 103, atransmission frame construction section 104, a reception dataconstruction section 115, and a reception buffer 116.

The communication control section 52 includes a gateway managementsection 105, a management information generation section 106, atransmission timing control section 107, a reception timing controlsection 113, and a management information processing section 114.

The baseband processing section 53 includes a transmission power controlsection 108, a wireless transmission processing section 109, an antennacontrol section 110, a wireless reception processing section 111, and adetection threshold control section 112.

The interface section 101 of the input/output section 51 functions as aninterface for exchanging data in the predetermined signal format withthe equipment control section 23 in FIG. 18. For example, the interfacesection 101 outputs to the transmission buffer 102 data to betransmitted fed from the equipment control section 23. Additionally, theinterface section 101 outputs to the equipment control section 23reception data obtained from another communication apparatus 11 andstored in the reception buffer 116.

The transmission buffer 102 temporarily stores the data to betransmitted. The data to be transmitted stored in the transmissionbuffer 102 is read at a predetermined timing by the transmission frameconstruction section 104.

The network management section 103 manages information representingfunctions for which the communication apparatus 11 takes responsibilityin the network. For example, in the case of taking responsibility forthe functions of the AC, the network management section 103 manages theaddresses of the communication apparatuses 11 included in the network.

Additionally, the network management section 103 manages functions forwhich responsibility is taken by other communication apparatuses 11belonging to the network, such as the communication apparatus 11operating as an AC and the communication apparatus 11 operating as anIG. The management of the network by the network management section 103is based on information fed from the interface section 101 and thegateway management section 105.

The network management section 103 outputs various types of informationsuch as addresses to each of the transmission frame construction section104, the gateway management section 105, and the reception dataconstruction section 115 as appropriate.

The transmission frame construction section 104 generates a data framein which the data stored in the transmission buffer 102 is transmittedand outputs the data frame to the wireless transmission processingsection 109.

The gateway management section 105 of the communication control section52 performs various types of control in accordance with the functions ofthe communication apparatus 11 itself managed by the network managementsection 103.

For example, in the case of operating as an AC, the gateway managementsection 105 outputs to the management information generation section 106management information including information for being stored in themanagement frame. Additionally, in the case of operating as an AC, thegateway management section 105 performs access control in accordancewith a predetermined communication protocol on the basis of, forexample, the information managed by the network management section 103.

In the case of operating as an IG, the gateway management section 105determines grant/rejection of connection of a communication apparatusrequesting Internet connection. Determination of grant/rejection of theconnection is based, for example, on a connection capacity correspondingto the capability of the communication apparatus 11 itself for Internetconnection. In the case of granting the Internet connection, the gatewaymanagement section 105 returns the Gateway Connection Grant frame andsubsequently manages transmission and reception of User Data by thecommunication apparatus to which the Internet connection has beengranted.

In the case of operating as a Station, the gateway management section105 selects the IG appropriate as a connection destination on the basisof the information included in the Gateway Announcement frames from theIGs and transmits the Gateway Connection Request frame to the selectedIG. In a case where Internet connection is granted, the gatewaymanagement section 105 makes the Internet connection via the IG selectedas the connection destination.

Transmission of each management frame by the gateway management section105 is performed by, for example, controlling the management informationgeneration section 106.

The management information generation section 106 generates a managementframe including the management information fed from the gatewaymanagement section 105 and outputs the management frame to the wirelesstransmission processing section 109.

The transmission timing control section 107 controls the transmissiontiming for the transmission of the frame by the wireless transmissionprocessing section 109 on the basis of the predetermined access controlprotocol. The transmission timing is specified by, for example, thegateway management section 105 or the reception timing control section113.

The transmission power control section 108 of the baseband processingsection 53 controls the transmission power for radio waves under thecontrol of the gateway management section 105 and the transmissiontiming control section 107.

As described above, the transmission power for radio waves from thecommunication apparatus 11 operating as an AC is kept at a level wherethe communication apparatus 11 can communicate with all thecommunication apparatuses 11 belonging to the network including the IG.

Additionally, the transmission power for radio waves from thecommunication apparatus 11 operating as an IG is kept at a level wherethe AC can communicate with the Station making Internet connection usingthe communication apparatus 11 itself.

The transmission power for radio waves from the communication apparatus11 operating as a Station is kept at a level where the AC cancommunicate with the IG used for Internet connection.

The wireless transmission processing section 109 converts into abaseband signal the data frame generated by the transmission frameconstruction section 104 and the management frame generated by themanagement information generation section 106. Additionally, thewireless transmission processing section 109 executes various types ofsignal processing such as modulation processing on the baseband signaland feeds the antenna control section 110 with the baseband signalsubjected to the signal processing.

The antenna control section 110 includes a plurality of antennasincluding antennas 25A and 25B connected together. The antenna controlsection 110 transmits from the antenna 25A and the antenna 25B a signalfed from the wireless transmission processing section 109. Additionally,in response to reception of a radio wave transmitted from anotherapparatus, the antenna control section 110 outputs to the wirelessreception processing section 111 a signal fed from the antenna 25A andthe antenna 25B.

The wireless reception processing section 111 detects, in the signal fedfrom the antenna control section 110, a preamble of the frametransmitted in the predetermined format and receives data succeeding thepreamble and included in a header and a data portion. The wirelessreception processing section 111 outputs the data in the managementframe such as the Beacon frame to the management information processingsection 114 and outputs to the reception data construction section 115the data in the data frame transmitted from another communicationapparatus 11.

The detection threshold control section 112 configures in the wirelessreception processing section 111 a threshold used as a reference fordetection of a signal such as a preamble. Configuration of the thresholdby the detection threshold control section 112 is performed under thecontrol of the gateway management section 105, for example, in a casewhere control of the transmission power for radio waves is performed inthe network.

The reception timing control section 113 of the communication controlsection 52 controls the reception timing for the reception of the frameby the wireless reception processing section 111. The reception timingis specified, for example, by the gateway management section 105.Information regarding the reception timing for the frame is fed to thetransmission timing control section 107 as appropriate on the basis ofthe predetermined access control protocol.

The management information processing section 114 analyzes themanagement frame including data fed from the wireless receptionprocessing section 111. In a case where the communication apparatus 11is specified as a destination of the management frame, the managementinformation processing section 114 extracts parameters stored in themanagement frame and analyzes the contents of the parameters. Themanagement information processing section 114 outputs informationregarding analysis results to the gateway management section 105 and thereception data construction section 115. The management informationprocessing section 114 also analyzes non-data packets as appropriate.

The reception data construction section 115 of the input/output section51 removes the header from the data frame including the data fed fromthe wireless reception processing section 111 to extract the dataportion. The reception data construction section 115 outputs the dataincluded in the extracted data portion to the reception buffer 116 asreception data.

The reception buffer 116 temporarily stores the reception data fed fromthe reception data construction section 115. The reception data storedin the reception buffer 116 is read at a predetermined timing by theinterface section 101 and output to the equipment control section 23.

The wireless communication module 25 includes the input/output section51, the communication control section 52, and the baseband processingsection 53, including the above-described sections. In a case where thefunctions of the AP are shared among the plurality of communicationapparatuses 11, the operation of each section is switched depending onthe functions for which each communication apparatus 11 takesresponsibility.

<Operations of Communication Apparatuses>

Now, operations of each of the communication apparatus 11 operating asan IG and the communication apparatus 11 operating as a Station will bedescribed.

Operations of IG

First, processing of the IG will be described with reference toflowcharts in FIG. 20 and FIG. 21.

In step S301, the equipment control section 23 of the IG acquires roleinformation regarding the IG. The role information, includinginformation representing the role (function) played by the IG, is, forexample, configured after roles are allocated by the processingdescribed with reference to FIG. 5 and is stored in a memory included inthe equipment control section 23.

In step S302, the equipment control section 23 determines whether or notthe communication apparatus 11 operates as an IG.

In the case of determining in step S302 that the communication apparatus11 operates as an IG, the equipment control section 23 acquires in stepS303 information representing the operating state of the Internetconnection module 21 to detect a connection state of the Internet. Theinformation representing the operating state of the Internet connectionmodule 21 indicates whether or not the IG is connected to the Internet.

In step S304, the equipment control section 23 determines whether or notInternet connection is present.

In a case where the equipment control section 23 determines in step S304that Internet connection is present, then in step S305, the networkmanagement section 103 of the wireless communication module 25configures Internet Gateway Parameter.

Internet Gateway Parameter is information related to the capability ofthe IG for Internet connection. Internet Gateway Parameter includes, forexample, information related to a provider, information related to acommunication speed, and information related to the connection capacity.The information related to the connection capacity identifies the numberof Stations to which the IG can grant Internet connection. Theinformation included in Internet Gateway Parameter is included invarious frames, which are then transmitted to the other communicationapparatuses 11, as appropriate.

In step S306, the gateway management section 105 determines whether ornot the Gateway Announcement frame used as a notification frame is to betransmitted at the current timing.

In the case of determining in step S306 that the Gateway Announcementframe is to be transmitted at the current timing, then in step S307, thegateway management section 105 transmits the Gateway Announcement frame.

Here, the Gateway Announcement frame including parameters acquired bythe gateway management section 105 is generated by the managementinformation generation section 106. The Gateway Announcement framegenerated by the management information generation section 106 is outputto the wireless transmission processing section 109 which then transmitsthe Gateway Announcement frame to the surrounding communicationapparatus 11. The Station having received the Gateway Announcement framespecifies as Internet Gateway the communication apparatus 11 havingtransmitted the Gateway Announcement frame, and in the case ofrequesting Internet connection, transmits the Gateway Connection Requestframe as appropriate.

In a case where the gateway management section 105 determines that theGateway Announcement frame is not to be transmitted at the currenttiming in step S306, the processing in step S307 is skipped.

In step S308, the gateway management section 105 determines whether ornot the Gateway Connection Request frame used as a connection requestfor Internet connection has been received.

In the case of being received by the wireless reception processingsection 111, the Gateway Connection Request frame is fed to themanagement information processing section 114 and analyzed. Parameterscorresponding to analysis results for the Gateway Connection Requestframe are fed from the management information processing section 114 tothe gateway management section 105. The Gateway Connection Request frameincludes the address of the source Station or the like as describedabove.

In the case of determining in step S308 that the Gateway ConnectionRequest frame has been received, then in step S309, the gatewaymanagement section 105 acquires the parameters for the GatewayConnection Request frame fed from the management information processingsection 114.

In step S310, the gateway management section 105 acquires theinformation related to the connection capacity included in InternetGateway Parameter managed by the network management section 103.

In step S311, the gateway management section 105 determines, forexample, on the basis of the information related to the connectioncapacity, whether or not Internet connection can be granted to theStation having transmitted the Gateway Connection Request frame.

As described above, the information related to the connection capacityidentifies the number of Stations to which the IG can grant Internetconnection. For example, in a case where the number of Stations to whichInternet connection has already been granted is smaller than the numberindicated in the information related to the connection capacity, thegateway management section 105 determines that Internet connection canbe granted.

In the case of determining in step S311 that Internet connection can begranted to the Station having transmitted the Gateway Connection Requestframe, then in step S312, the gateway management section 105 returns theGateway Connection Grant frame.

Here, the management information generation section 106 generates theGateway Connection Grant frame including the parameters acquired by thegateway management section 105. The Gateway Connection Grant framegenerated by the management information generation section 106 is outputto the wireless transmission processing section 109 which then transmitsthe Gateway Connection Grant frame to the Station having transmitted theGateway Connection Request frame.

In step S313, the gateway management section 105 registers the addressof the Station having transmitted the Gateway Connection Request frameas Target Address. After registering the address, the gateway managementsection 105 controls the Internet connection made by the Station withthe address registered as Target Address. Target Address is the addressof the Station to which Internet connection is granted. After theregistration of Target Address, the processing ends.

In a case where the equipment control section 23 determines in step S302that the communication apparatus 11 does not operate as an IG, a casewhere the equipment control section 23 determines in step S304 that theIG is not connected to the Internet, or a case where the gatewaymanagement section 105 determines in step S311 that granting Internetconnection is disabled, the processing also ends.

On the other hand, in a case where the gateway management section 105determines in step S308 that the Gateway Connection Request frame hasnot been received, the processing proceeds to step S314 (FIG. 21).

In step S314, the gateway management section 105 determines whether ornot a data frame transmitted by a predetermined Station has beenreceived. The data frame includes uplink User Data transmitted by theStation.

The data frame received by the wireless reception processing section 111is analyzed by the reception data construction section 115, and the UserData is extracted. The data frame includes the address of the source ofthe data frame. The address of the source included in the data frame is,for example, extracted by the management information processing section114 and fed to the gateway management section 105.

In step S315, the gateway management section 105 acquires the address ofthe source of the data frame.

In step S316, the gateway management section 105 determines whether ornot the address of the source is registered as Target Address.

In the case of determining in step S316 that the address of the sourceis registered as Target Address, then in step S317, the gatewaymanagement section 105 returns an ACK frame as necessary.

In step S318, the interface section 101 outputs to the equipment controlsection 23 the User Data extracted from the data frame and stored in thereception buffer 116 and transfers the User Data to the Internet side.The User Data extracted from the data frame is output from the equipmentcontrol section 23 to the Internet connection module 21 which thentransmits the User Data to an external apparatus on the Internetcorresponding to a destination.

After the uplink data is transmitted as described above, the processingproceeds to step S319. In a case where the gateway management section105 determines in step S314 that the data frame has not been received ordetermines in step S316 that the address of the source of the data frameis not registered as Target Address, the processing also proceeds tostep S319.

In step S319, the gateway management section 105 determines whether ornot data from the Internet side has been received.

Downlink data transmitted from an external apparatus on the Internet isreceived at the Internet connection module 21 which feeds the downlinkdata to the wireless communication module 25 via the equipment controlsection 23. The downlink data fed to the wireless communication module25 is fed from the interface section 101 to the transmission buffer 102where the downlink data is stored. Additionally, the address included inthe downlink data and specifying the data destination is fed to thegateway management section 105 via the network management section 103.

In step S320, the gateway management section 105 acquires the address ofthe destination fed via the network management section 103.

In step S321, the gateway management section 105 determines whether ornot the address of the destination is registered as Target Address.

In a case where the gateway management section 105 determines in stepS321 that the address of the destination is registered as TargetAddress, then in step S322, the transmission frame construction section104 generates a data frame including as User Data the data stored in thetransmission buffer 102 and causes the wireless transmission processingsection 109 to transmit the data frame on the basis of the predeterminedaccess control protocol.

After the downlink data is transmitted as described above, theprocessing proceeds to step S323. In a case where the gateway managementsection 105 determines in step S319 that no data from the Internet sidehas been received or determines in step S321 that the address of thedestination is not registered as Target Address, the processing alsoproceeds to step S323.

In step S323, the gateway management section 105 determines whether ornot the Gateway Disconnection Request frame corresponding to a requestfor cancellation of Internet connection has been received.

In the case of being received by the wireless reception processingsection 111, the Gateway Disconnection Request frame is fed to themanagement information processing section 114 and analyzed. Parameterscorresponding to analysis results for the Gateway Disconnection Requestframe are fed from the management information processing section 114 tothe gateway management section 105. The Gateway Disconnection Requestframe includes the address of the source Station or the like asdescribed above.

In the case of determining in step S323 that the Gateway DisconnectionRequest frame has been received, then in step S324, the gatewaymanagement section 105 transmits the Gateway Disconnection Grant frame.

Here, the Gateway Disconnection Grant frame is generated by themanagement information generation section 106. The Gateway DisconnectionGrant frame generated by the management information generation section106 is output to the wireless transmission processing section 109 whichthen transmits the Gateway Disconnection Grant frame to the Stationhaving transmitted the Gateway Disconnection Request frame.

In step S325, the gateway management section 105 deletes from TargetAddress the address of the Station having transmitted the GatewayDisconnection Request frame, cancelling the registration.

In step S326, the network management section 103 updates the informationrelated to the connection capacity and manages Internet GatewayParameter including the updated information.

After Internet Gateway Parameter is updated or in a case where thegateway management section 105 determines in step S323 that the GatewayDisconnection Request frame has not been received, the processing ends.

In the communication apparatus 11 operating as an IG, theabove-described series of steps of processing is repeatedly executedwhile Internet connection remains established. The Gateway Announcementframe is repeatedly transmitted to repeatedly notify surroundingStations that the IG is present.

Operations of Station

Now, processing of the Station will be described with reference toflowcharts in FIG. 22 and FIG. 23. Descriptions overlapping the abovedescriptions are omitted as appropriate.

In step S401, the equipment control section 23 of the Station acquiresrole information regarding the Station.

In step S402, the equipment control section 23 determines whether or notthe communication apparatus 11 operates as a Station.

In a case where the equipment control section 23 determines in step S402that the communication apparatus 11 operates as a Station, then in stepS403, the gateway management section 105 whether or not the GatewayAnnouncement frame has been received.

In the case of being received by the wireless reception processingsection 111, the Gateway Announcement frame is fed to the managementinformation processing section 114 which then analyzes the GatewayAnnouncement frame. Parameters corresponding to analysis results for theGateway Announcement frame are fed from the management informationprocessing section 114 to the gateway management section 105. TheGateway Announcement frame includes the address of the source IG or thelike as described above.

In the case of determining in step S403 that the Gateway Announcementframe has been received, then in step S404, the gateway managementsection 105 acquires Internet Gateway Parameter included in the GatewayAnnouncement frame fed from the management information processingsection 114.

In step S405, the gateway management section 105 determines whether ornot any of the IGs is configured for use for Internet connection. In acase where a predetermined IG is used for Internet connection, thegateway management section 105 determines that any of the IGs isconfigured for Internet connection. Additionally, in a case where noInternet connection has been made, none of the IGs is configured forInternet connection.

In the case of determining in step S405 that none of the IGs isconfigured for Internet connection, then in step S406, the gatewaymanagement section 105 transmits the Gateway Connection Request frame.

Here, the management information generation section 106 generates theGateway Connection Request frame including the parameters acquired bythe gateway management section 105. The Gateway Connection Request framegenerated by the management information generation section 106 is outputto the wireless transmission processing section 109 which then transmitsthe Gateway Connection Request frame to the IG having transmitted theGateway Announcement frame.

In step S407, the gateway management section 105 determines whether ornot the Gateway Connection Grant frame, corresponding to a notificationfor grant of Internet connection, has been received by a predeterminedwaiting time.

As described above, the IG determines whether or not to grant Internetconnection to the Station having transmitted the Gateway ConnectionRequest frame, and in a case where the Internet connection is granted,the Gateway Connection Grant frame is returned.

In the case of determining in step S407 that the Gateway ConnectionGrant frame has been received, then in step S408, the gateway managementsection 105 registers as an IG used for Internet connection the IGhaving transmitted the Gateway Connection Grant frame. For example, theaddress of the IG included in the Gateway Connection Grant frame isregistered as the destination of uplink data and as the source ofdownlink data.

On the other hand, in the case of determining in step S405 that any ofthe IGs has already been configured for Internet connection, then instep S409, the gateway management section 105 acquires informationrelated to the connection state of the existing IG. For example,information related to the intensity of radio waves from the IG used forInternet connection is acquired as information related to the connectionstate of the existing IG.

In step S410, the gateway management section 105 determines whether ornot a new IG is in a better connection state. For example, the intensityof radio waves from the new IG is compared with the intensity of radiowaves from the existing IG, and the IG with the higher intensity ofradio waves is determined to be the IG in the better connection state.

In the case of determining the new IG to be in the better connectionstate in step S410, then in step S411, the gateway management section105 transmits the Gateway Disconnection Request frame to the existingIG.

Here, the management information generation section 106 generates theGateway Disconnection Request frame including the parameters acquired bythe gateway management section 105. The Gateway Disconnection Requestframe generated by the management information generation section 106 isoutput to the wireless transmission processing section 109 which thentransmits the Gateway Disconnection Request frame to the existing IG.The existing IG returns the Gateway Disconnection Grant frame.

In step S412, the gateway management section 105 determines whether ornot the Gateway Disconnection Grant frame, corresponding to anotification of completion of Internet connection cancellation, has beenreceived.

In a case where the gateway management section 105 determines in stepS412 that the Gateway Disconnection Grant frame has been received, theprocessing proceeds to step S406, and the subsequent processing isexecuted.

Specifically, in a case where the Gateway Connection Request frame istransmitted to the new IG and the Gateway Connection Grant frame isreturned, the IG registration is changed. Thus, instead of the existingIG, the new IG is used to make Internet connection.

In a case where the IG is registered in step S408 or a case where theequipment control section 23 determines in step S402 that thecommunication apparatus 11 does not operate as a Station, the processingends. In a case where the gateway management section 105 determines instep S407 that the Gateway Connection Grant frame has not been receivedor determines in step S412 that the Gateway Disconnection Grant framehas not been received, the processing also ends.

On the other hand, in a case where the gateway management section 105determines in step S403 that the Gateway Announcement frame has not beenreceived or determines in step S410 that the new IG is in the worseconnection state, the processing proceeds to step S413 (FIG. 23).

In step S413, the interface section 101 determines whether or nottransmission data has been fed. For example, in a case where datagenerated by an application executed by the equipment control section 23is transmitted to an external apparatus as uplink data, User Data usedas transmission data is fed from the equipment control section 23.

In a case where the interface section 101 determines in step S413 thatthe transmission data has been fed, then in step S414, the interfacesection 101 acquires the User Data.

In step S415, the gateway management section 105 determines whether ornot the User Data can be transmitted. Here, in a case where the IGregistration has already been performed in step S408, the gatewaymanagement section 105 determines that the User Data can be transmitted.

In a case where the gateway management section 105 determines in stepS415 that the User Data can be transmitted, then in step S416, thetransmission frame construction section 104 reads the User Data from thetransmission buffer 102 and configures the address of the IG to generatea data frame. Information regarding the address of the IG used as thedestination of the data frame is fed from the gateway management section105 to the transmission frame construction section 104 via the networkmanagement section 103.

In step S417, the wireless transmission processing section 109 transmitsthe data frame to the IG. Transmission of the data frame to the IG istimed to coincide with transmission of a data frame by another Stationas appropriate as described with reference to FIG. 11.

After the transmission of the uplink data is performed as describedabove, the processing proceeds to step S418. In a case where theinterface section 101 determines in step S413 that the transmission datahas not been fed or a case where the gateway management section 105determines in step S415 that the User Data fails to be transmitted, theprocessing also proceeds to step S418.

In step S418, the gateway management section 105 determines whether ornot the ACK frame has been received via the management informationprocessing section 114.

In a case where the gateway management section 105 determines in stepS418 that the ACK frame has been received, then in step S419, thetransmission frame construction section 104 discards the User Datastored in the transmission buffer 102. In a case where the gatewaymanagement section 105 determines in step S418 that no ACK frame hasbeen received, the processing in step S419 is skipped.

In step S420, the gateway management section 105 determines whether ornot the User Data destined for the Station itself has been received. Forexample, downlink data transmitted from an external apparatus andreceived at the IG is transmitted from the IG using a data frame.

In a case where the gateway management section 105 determines in stepS420 that the data destined for the Station itself has been received,then in step S421, the reception data construction section 115 extractsthe User Data from the data frame and stores the User Data in thereception buffer 116.

In step S422, the gateway management section 105 returns the ACK frameto the IG. Reception of the data frame from the IG is performed asappropriate, and as an example, is timed to coincide with reception of adata frame by another Station as described with reference to FIG. 11.

In step S423, the gateway management section 105 determines whether ornot all of the series of downlink data has been received or apredetermined output timing has elapsed.

In a case where the gateway management section 105 determines in stepS423 that all of the data has been received or the predetermined outputtiming has elapsed, then in step S424, the interface section 101 readsthe downlink data from the reception buffer 116 and transfers thedownlink data to connected equipment such as the information outputmodule 24.

After the downlink data has been transferred, the processing ends. In acase where the gateway management section 105 determines in step S420that no data destined for the Station itself has been received ordetermines in step S423 that not all of the series of downlink data hasbeen received, the processing also ends.

As described above, provision of a plurality of communicationapparatuses managing Internet connection allows the load of the Internetconnection to be distributed.

Additionally, because each Station selects the closest IG for Internetconnection, the required transmission power for radio waves can beminimized, and data transmission can be achieved at a highercommunication rate.

The predetermined IG-Station communication and the another IG-Stationcommunication can be simultaneously performed in the same space,enabling the utilization efficiency of transmission paths to be improvedusing spatial multiplexing of multiuser MIMO (Multi-Input Multi-Output)or the like.

<Examples of Parameters>

In the above description, the Station selects the IG on the basis of theintensity of radio waves. However, the selection may be based on thevarious parameters included in the Gateway Announcement frame. In thiscase, the IG that is located close and that is in a good connectionstate is not always selected, but the IG used for Internet connection isselected on the basis of various criteria.

The Gateway Announcement frame transmitted from the IG includes GatewayParameter, Gateway Attribute, and Gateway Control as described withreference to FIG. 13. The IG is selected using these parameters.

FIG. 24 is a diagram illustrating examples of parameters included inGateway Parameter.

Gateway Parameter includes parameters varying with state and included inthe parameters related to the Internet connection capability.

As illustrated in FIG. 24, Gateway Parameter includes Usage Channels,Resource Unit Bandwidth, Protocol Version, TTL Value, Hop Value, AverageSpeed, Connect Counts, Usage MCS, Usage TX Power, and AvailableCapacity.

Usage Channels represent channels (frequency bands) that are included inavailable channels in the wireless LAN network and that are in actualuse.

Resource Unit Bandwidth represents a bandwidth of a resource unit.

Protocol Version represents a version of a protocol in use.

TTL Value represents a value of Time To Live in the wireless LANnetwork.

Hop Value represents the number of connection hops.

Average Speed represents an average speed of communication.

Connect Counts represent the number of connected devices in use.

Usage MCS represents available modulation schemes and coding rates.

Usage TX Power represents the transmission power in use.

Available Capacity represents an available connection capacity.

The communication apparatus 11 operating as an IG configures values forthese parameters according to a communication status and transmits theparameters in the Gateway Announcement frame.

The communication apparatus 11 operating as a Station analyzes theGateway Announcement frame and makes determinations such as selection ofthe IG having, for example, the highest communication speed representedby Average Speed included in Gateway Parameter.

These types of information may be described in the Gateway Announcementframe as parameters in bit map format indicating available portions. Thebit map format is a format including information indicating that thebits of the currently supported parameter, included in the parameterswith values varying with status, are effective.

FIG. 25 is a diagram illustrating examples of parameters includedGateway Attribute.

Gateway Attribute includes invariable parameters included in theparameters related to the capability of the IG for Internet connection.

As illustrated in FIG. 25, Gateway Attribute includes Frequency Bands,Channel Bandwidth, W-LAN Type, Country Code, Support Protocol, ConnectCost, Device Counts, Support MCS, MAX TX Power, and Max Capacity.

Frequency Bands represent frequency bands (2.4 GHz, 5 GHz, and the like)that are available for the IG.

Channel Bandwidth represents a channel width utilized by the IG.

W-LAN Type represents wireless LAN communication standards(802.11a/b/g/n/ac/ad/ah/ax or the like) supported by the IG.

Country Code represents a country in which the IG is installed.

Support Protocol represents a generation of a protocol implemented inthe IG.

Connection Cost represents a cost of Internet connection.

Device Counts represent a maximum number of Stations to which Internetconnection is granted.

Support MCS represents MCS supported by the IG.

Max TX Power represents a maximum transmission power of the IG.

Max Capacity represents a maximum connection capacity of the IG.

The communication apparatus 11 operating as an IG configures fixedvalues for these parameters and transmits the parameters in the GatewayAnnouncement frame. Information including the parameter values may beacquired from a predetermined server via the Internet.

The communication apparatus 11 operating as a Station analyzes theGateway Announcement frame and makes determinations such as selection ofthe IG involving, for example, the lowest cost represented by ConnectionCost included in Gateway Attribute.

FIG. 26 is a diagram illustrating examples of parameters included inGateway Control.

Gateway Control includes parameters configured by the user andparameters configured in accordance with instructions from apredetermined apparatus on the network.

As illustrated in FIG. 26, Gateway Control includes Gateway IP Address,Local Address, User Select Information, Priority Gateway, ConnectionDomain, Connection Policy, Vendor Info, and Support Parameter.

Gateway IP Address represents an IP address of the IG configured forconnection to the Internet.

Local Address represents a local address of the IG.

User Select Information represents that the IG is specified by the userto be used for Internet connection.

Priority Gateway represents a priority of the IG used for Internetconnection.

Connection Domain represents a domain of the connection destination.

Connection Policy represents a connection policy configured by the user.

Vender Info represents information regarding a vender of the IG.

Support Parameter is information configured by the user to be supported.

The communication apparatus 11 operating as an IG configures values forthese parameters according to a configuration status of the user or thelike and transmits the parameters in the Gateway Announcement frame.

The communication apparatus 11 operating as a Station analyzes theGateway Announcement frame and makes determinations such as selection ofthe IG having, for example, the highest priority represented by PriorityGateway included in Gateway Control.

The selection of the IG by the Station may be based on a combination ofa plurality of the parameters as described above and included in GatewayParameter, Gateway Attribute, or Gateway Control, instead of one of theparameters.

<Example of Communication Relayed Through AC>

In the above description, the communication apparatus 11 operating as aStation selects one of the plurality of IGs that can communicatedirectly with the communication apparatus 11. However, the IG that failsto communicate directly with the communication apparatus 11 may be usedfor Internet connection.

In this case, each Station can select not only the IG located at such aplace that the Station operates as a Near Station but also the IGlocated at such a place that the Station operates as a Far Station, asthe IG used for Internet connection. As described above, NearStation/Far Station is an attribute determined on the basis of thepositional relation between the IG and the Station.

Communication between a certain IG and a Station operating as a FarStation when the position of the IG is assumed as a reference is relayedby the AC.

FIG. 27 is a diagram illustrating an example of a flow of uplink datatransmitted by a Far Station.

A configuration of a network illustrated in FIG. 27 is the same as theconfiguration described with reference to FIG. 1. With the InternetGateway 1 used as a reference, the Station 1 and the Station 2, whichcan communicate directly with the Internet Gateway 1, operate as NearStations. The Station 3 and the Station 4, which fail to communicatedirectly with the Internet Gateway 1 but are present within thereachable range of radio waves from the AC, operate as Far Stations. TheStation 3 and the Station 4 operating as Far Stations are assumed toselect the Internet Gateway 1 as an IG used for Internet connection.

In this case, as indicated by blank arrows A201 and A202, uplink datatransmitted to an external apparatus by the Station 3 is relayed by theAC and received by the Internet Gateway 1 which transmits the uplinkdata to the destination external apparatus.

Additionally, as indicated by blank arrows A203 and A204, uplink datatransmitted to an external apparatus by the Station 4 is relayed by theAC and received by the Internet Gateway 1 which transmits the uplinkdata to the destination external apparatus.

FIG. 28 is a diagram illustrating an example of a flow of downlink datato the Far Station.

As illustrated by blank arrows A211 and A212, downlink data for theStation 3 transmitted from an external apparatus and received at theInternet Gateway 1 is transmitted from the Internet Gateway 1 to theStation 3 via the AC.

As illustrated by blank arrows A213 and A214, downlink data for theStation 4 transmitted from an external apparatus and received at theInternet Gateway 1 is transmitted from the Internet Gateway 1 to theStation 4 via the AC.

As described above, in the case of selecting the Internet Gateway 1 asan IG used for Internet connection, the Station 3 and the Station 4,operating as Far Stations can communicate with the Internet Gateway 1via the AC. Accordingly, the AC includes a function for relaying thecommunication between the IG and the Station.

With reference to a sequence in FIG. 29, a series of steps of processingfor selecting the IG used for Internet connection will be described.

The sequence illustrated in FIG. 29 indicates processing in which, forexample, the Station 3 which operates as a Far Station when the InternetGateway 1 is used as a reference makes Internet connection using theInternet Gateway 1 and subsequently switches the connection destinationto the Internet Gateway 2 located closest. For example, the InternetGateway 2 is an IG configured after the Internet Gateway 1.

The example in FIG. 29 illustrates processing of the Internet Gateway 1,processing of the AC, processing of the Station 3 operating as a FarStation, and processing of the Internet Gateway 2 in this order from theleft.

In step S501, the Internet Gateway 1 transmits the Gateway Announcementframe indicating that the Internet Gateway 1 operates as an IG.

The Gateway Announcement frame may include the Action frame or includethe Management frame. In a case where the Internet Gateway 1 alsofunctions as the AC, the information in the Gateway Announcement framemay be included in the Beacon frame for transmission.

The Gateway Announcement frame transmitted from the Internet Gateway 1is received by the AC in step S521 and transmitted to the Station 3 instep S522 as Relay data. Note that in a case where any Far Station ispresent as viewed from the Internet Gateway 1, the Gateway Announcementframe may be relayed by the AC.

As described above, the Gateway Announcement frame transmitted by theInternet Gateway 1 is relayed by the AC and delivered throughout thenetwork around the AC. The Gateway Announcement frame is directlydelivered to the Near Station without being relayed by the AC.

In step S561, the Station 3 receives the Gateway Announcement framerelayed by the AC.

In step S562, the Station 3 transmits the Gateway Connection Requestframe requesting Internet connection using the Internet Gateway 1 as adestination.

The Gateway Connection Request frame transmitted from Station 3 isreceived by the AC in step S523 and transmitted to the Internet Gateway1 in step S524 as Relay data.

In step S502, the Internet Gateway 1 receives the Gateway ConnectionRequest frame relayed by the AC.

In a case where the request from the Station 3 is accepted, then in stepS503, the Internet Gateway 1 returns the Gateway Connection Grant frameusing the Station 3 as a destination. The Gateway Connection Grant frametransmitted by the Internet Gateway 1 represents that Internetconnection is granted.

The Gateway Connection Grant frame transmitted from the Internet Gateway1 is received by the AC in step S525 and transmitted to the Station 3 instep S526 as Relay data.

In step S563, the Station 3 receives the Gateway Connection Grant framerelayed by the AC. Accordingly, the Station 3 connects to the Internetvia the Internet Gateway 1 and is enabled to communicate with anexternal apparatus. Communication between the Station 3 and the InternetGateway 1 is relayed by the AC.

For example, uplink User Data is transmitted from the Station 3 to theInternet Gateway 1 via the AC as indicated by blank arrows A251 and A252and transmitted via the Internet Gateway 1 to the external apparatus asindicated by blank arrow A253. The ACK representing receiptacknowledgement is returned from the Internet Gateway 1 having receivedthe User Data to the Station 3 via the AC as indicated by arrows A254and A255.

Here, in step S581, the Internet Gateway 2 transmits the GatewayAnnouncement frame indicating that the Internet Gateway 2 operates as anIG.

The Gateway Announcement frame transmitted from the Internet Gateway 2is received by the Station 3 in step S264 and received by the AC in stepS527.

The Station 3 having received the Gateway Announcement frame selectsInternet connection using the Internet Gateway 2. The determination inthis case is based, for example, on the parameters included in theGateway Announcement frame or on a radio wave reception status.

In step S565, the Station 3 transmits the Gateway Disconnection Requestframe requesting cancellation of Internet connection using, as adestination, the Internet Gateway 1 corresponding to the existing IG.

The Gateway Disconnection Request frame transmitted from the Station 3is received by the AC in step S528 and transmitted to the InternetGateway 1 in step S529 as Relay data.

In step S504, the Internet Gateway 1 receives the Gateway DisconnectionRequest frame relayed by the AC.

In a case where the request from the Station 3 is accepted, then in stepS505, the Internet Gateway 1 returns the Gateway Disconnection Grantframe using the Station 3 as a destination.

The Gateway Disconnection Grant frame transmitted from the InternetGateway 1 is received by the AC in step S530 and transmitted to theStation 3 in step S531 as Relay data.

In step S566, the Station 3 receives the Gateway Disconnection Grantframe relayed by the AC.

In step S567, the Station 3 transmits to the Internet Gateway 2 theGateway Connection Request frame requesting Internet connection.Transmission of the Gateway Connection Request frame to the InternetGateway 2 is directly performed without being relayed by the AC.

In step S582, the Internet Gateway 2 receives the Gateway ConnectionRequest frame transmitted from the Station 3. In a case where therequest from the Station 3 is accepted, then in step S583, the InternetGateway 2 returns the Gateway Connection Grant frame.

In step S568, the Station 3 receives the Gateway Connection Grant frametransmitted from the Internet Gateway 2. Accordingly, the Station 3connects to the Internet via the Internet Gateway 2 and is enabled tocommunicate with an external apparatus.

Uplink User Data is directly transmitted from the Station 3 to theInternet Gateway 2 as indicated by blank arrow A261 and transmitted viathe Internet Gateway 2 to the external apparatus as indicated by blankarrow A262. The ACK representing receipt acknowledgement is directlyreturned from the Internet Gateway 2 having received the User Data tothe Station 3 as indicated by arrow A263.

As described above, the IG located where the IG is precluded from directcommunication may be enabled to be selected as an IG used for Internetconnection.

<Modified Examples>

A single station may be enabled to switch the IG used for Internetconnection depending on the type of data. For example, a predeterminedIG may be enabled to be selected as an IG used for transmission ofuplink data, and another IG may be enabled to be selected as an IG usedfor reception of downlink data.

In the above-described case, the functions of the AC, the functions ofthe IG, and the functions of the IC are distributed. The functions ofthe AP may be further subdivided and the functions resulting from thesubdivision may be distributed among more communication apparatuses 11.

In the network as described above in which the functions of the AP areshared among the plurality of communication apparatuses 11, datatransmission based on OFDMA may be used instead of the data transmissionbased on multiuser MIMO.

Configuration Example of Computer

The above-described series of steps of processing can be executed byhardware or by software. In a case where the series of steps ofprocessing is executed by software, a program included in the softwareis installed from a program recording medium into a computer integratedin dedicated hardware, a general-purpose personal computer, or the like.

FIG. 30 is a block diagram illustrating a configuration example ofhardware of a computer executing the above-described series of steps ofprocessing using the program.

A CPU (Central Processing Unit) 1001, a ROM (Read Only Memory) 1002, anda RAM (Random Access Memory) 1003 are connected together by a bus 1004.

An input/output interface 1005 is further connected to the bus 1004. Theinput/output interface 1005 connects to an input section 1006 includinga keyboard, a mouse, and the like, and an output section 1007 includinga display, a speaker, and the like. Additionally, the input/outputinterface 1005 connects to a storage section 1008 including a hard disk,a nonvolatile memory, and the like, a communication section 1009including a network interface, and a drive 1010 driving a removablemedium 1011.

In the computer configured as described above, the CPU 1001 performs theabove-described series of steps of processing by loading a programstored in the storage section 1008 into the RAM 1003 via theinput/output interface 1005 and the bus 1004 and executing the program.

The program executed by the CPU 1001 is provided in the removable medium1011 in which the program is recorded or is provided via a wired orwireless transmission medium such as a local area network, the Internet,or digital broadcasting and is then installed in the storage section1008.

Note that the program executed by the computer may be a programchronologically executing processing along the order described herein ora program executing processing in parallel or at required timings wheninvocation is performed or the like.

The system as used herein means a set of a plurality of components(apparatuses, modules (parts), and the like) regardless of whether ornot all of the components lie inside the same housing. Accordingly, thesystem refers to both a plurality of apparatuses contained in separatehousings and connected together via a network and one apparatusincluding a plurality of modules contained in one housing.

Note that effects described herein are only illustrative and are notrestrictive, and that other effects may be produced.

The embodiments of the present technique are not limited to theabove-described embodiment, but various changes can be made to theembodiment without departing from the spirits of the present technique.

For example, the present technique can be configured as cloud computingin which one function is shared among a plurality of apparatuses via thenetwork.

Additionally, the steps described in the above-described flowcharts canbe executed by one apparatus or shared among a plurality of apparatuses.

Furthermore, in a case where one step includes a plurality of types ofprocessing, not only can the plurality of types of processing includedin the one step be executed by one apparatus but also be shared among aplurality of apparatuses for execution.

Example of Combination of Components

The present technique can also be configured as follows.

(1)

A communication apparatus included in a wireless LAN including aplurality of communication apparatuses functioning as gateways, thecommunication apparatus including:

a communication control section configured to transmit, when the subjectcommunication apparatus is connected to an external network, amanagement frame including a parameter related to a capability ofconnecting to the external network, to another apparatus within thewireless LAN.

(2)

The communication apparatus according to (1) described above, in whichthe communication control section controls connection to the externalnetwork made by the another apparatus.

(3)

The communication apparatus according to (2) described above, in whichthe communication control section receives connection requestinformation transmitted from the another apparatus and representing arequest for connection to the external network and, in a case where theconnection to the external network is granted, transmits to the anotherapparatus grant information representing that the connection to theexternal network is granted.

(4)

The communication apparatus according to (3) described above, in whichthe communication control section determines, on the basis of aconnection capacity, whether or not connection to the external networkis granted to the another apparatus having transmitted the connectionrequest information.

(5)

The communication apparatus according to (3) or (4) described above, inwhich, in a case where cancellation request information representing arequest for cancellation of the connection to the external network istransmitted from the another apparatus, the communication controlsection terminates the connection to the external network.

(6)

The communication apparatus according to (5) described above, in whichthe cancellation request information includes an address of the subjectcommunication apparatus newly used for the connection to the externalnetwork by the another apparatus.

(7)

The communication apparatus according to any one of (1) to (6) describedabove, in which the communication control section controls transmissionpower for radio waves within a range in which communication with theanother apparatus within a network is enabled.

(8)

The communication apparatus according to (7) described above, in whichthe another apparatus within the network includes a control apparatusresponsible for a function for access control in the wireless LAN.

(9)

The communication apparatus according to (2) described above, in whichthe communication control section performs transmission of data to theanother apparatus at a timing overlapping a timing for transmission ofdata by the communication apparatus responsible for the function of thegateway.

(10)

The communication apparatus according to (2) described above, in whichthe communication control section performs reception of data transmittedfrom the another apparatus at a timing overlapping a timing forreception of data by the communication apparatus responsible for thefunction of the gateway.

(11)

A communication apparatus including:

a communication control section configured to receive a management frametransmitted from a predetermined apparatus connected to an externalnetwork and included in a plurality of predetermined apparatusesfunctioning as gateways for a wireless LAN, the management frameincluding a parameter related to a capability of connecting to theexternal network, the communication control section transmitting, to anyone of the predetermined apparatuses, connection request informationrepresenting a request for connection to the external network.

(12)

The communication apparatus according to (11) described above, in whichthe communication control section receives grant information transmittedfrom the predetermined apparatus to which the connection requestinformation is transmitted, the grant information representing thatconnection to the external network is granted, and

the communication apparatus further includes:

a management section configured to register the predetermined apparatushaving transmitted the grant information, as a gateway used for theconnection to the external network.

(13)

The communication apparatus according to (12) described above, in whichthe management section selects, on the basis of a connection capabilityof each predetermined apparatus represented by the parameter, thepredetermined apparatus requesting connection to the external network,and

the communication control section transmits the connection requestinformation to the predetermined apparatus selected.

(14)

The communication apparatus according to (13) described above, in which,in a case where the predetermined apparatus requesting connection to theexternal network is newly selected, the communication control sectiontransmits, to the predetermined apparatus, cancellation requestinformation representing a request for cancellation of the connection tothe external network.

(15)

The communication apparatus according to any one of (11) to (14)described above, in which the communication control section controlstransmission power for radio waves within a range in which communicationwith another apparatus within a network is enabled.

(16)

The communication apparatus according to (15) described above, in whichthe another apparatus within the network includes a control apparatusresponsible for a function for access control in the wireless LAN.

(17)

The communication apparatus according to (12) described above, in whichthe communication control section performs transmission of data to thepredetermined apparatus at a timing overlapping a timing fortransmission, by the another apparatus within the wireless LAN, of datato another of the predetermined apparatuses responsible for the functionof the gateway.

(18)

The communication apparatus according to (12) described above, in whichthe communication control section performs reception of data transmittedfrom the predetermined apparatus at a timing overlapping a timing forreception, by the another apparatus, of data transmitted by another ofthe predetermined apparatuses responsible for the function of thegateway.

(19)

A communication system including:

a first communication apparatus included in a wireless LAN including aplurality of communication apparatuses functioning as gateways, thefirst communication apparatus including

-   -   a communication control section configured to transmit, when the        first communication apparatus is connected to an external        network, a management frame including a parameter related to a        capability of connecting to the external network, to another        apparatus within the wireless LAN; and

a second communication apparatus operating as the first communicationapparatus and including

-   -   a communication control section configured to receive the        management frame transmitted from the first communication        apparatus and transmit, to the first communication apparatus,        connection request information representing a request for        connection to the external network.

REFERENCE SIGNS LIST

-   11 Communication apparatus-   21 Internet connection module-   22 Information input module-   23 Equipment control section-   24 Information output module-   25 Wireless communication module-   51 Input/output section-   52 Communication control section-   53 Baseband processing section-   101 Interface section-   102 Transmission buffer-   103 Network management section-   104 Transmission frame construction section-   105 Gateway management section-   106 Management information generation section-   107 Transmission timing control section-   108 Transmission power control section-   109 Wireless transmission processing section-   110 Antenna control section-   111 Wireless reception processing section-   112 Detection threshold control section-   113 Reception timing control section-   114 Management information processing section-   115 Reception data construction section-   116 Reception buffer

1. A communication apparatus included in a wireless LAN including aplurality of communication apparatuses functioning as gateways, thecommunication apparatus comprising: a communication control sectionconfigured to transmit, when the subject communication apparatus isconnected to an external network, a management frame including aparameter related to a capability of connecting to the external network,to another apparatus within the wireless LAN.
 2. The communicationapparatus according to claim 1, wherein the communication controlsection controls connection to the external network made by the anotherapparatus.
 3. The communication apparatus according to claim 2, whereinthe communication control section receives connection requestinformation transmitted from the another apparatus and representing arequest for connection to the external network and, in a case where theconnection to the external network is granted, transmits to the anotherapparatus grant information representing that the connection to theexternal network is granted.
 4. The communication apparatus according toclaim 3, wherein the communication control section determines, on abasis of a connection capacity, whether or not connection to theexternal network is granted to the another apparatus having transmittedthe connection request information.
 5. The communication apparatusaccording to claim 3, wherein, in a case where cancellation requestinformation representing a request for cancellation of the connection tothe external network is transmitted from the another apparatus, thecommunication control section terminates the connection to the externalnetwork.
 6. The communication apparatus according to claim 5, whereinthe cancellation request information includes an address of the subjectcommunication apparatus newly used for the connection to the externalnetwork by the another apparatus.
 7. The communication apparatusaccording to claim 1, wherein the communication control section controlstransmission power for radio waves within a range in which communicationwith the another apparatus is enabled.
 8. The communication apparatusaccording to claim 7, wherein the another apparatus includes a controlapparatus responsible for a function for access control in the wirelessLAN.
 9. The communication apparatus according to claim 2, wherein thecommunication control section performs transmission of data to theanother apparatus at a timing overlapping a timing for transmission ofdata by the communication apparatus responsible for the function of thegateway.
 10. The communication apparatus according to claim 2, whereinthe communication control section performs reception of data transmittedfrom the another apparatus at a timing overlapping a timing forreception of data by the communication apparatus responsible for thefunction of the gateway.
 11. A communication apparatus comprising: acommunication control section configured to receive a management frametransmitted from a predetermined apparatus connected to an externalnetwork and included in a plurality of predetermined apparatusesfunctioning as gateways for a wireless LAN, the management frameincluding a parameter related to a capability of connecting to theexternal network, the communication control section transmitting, to anyone of the predetermined apparatuses, connection request informationrepresenting a request for connection to the external network.
 12. Thecommunication apparatus according to claim 11, wherein the communicationcontrol section receives grant information transmitted from thepredetermined apparatus to which the connection request information istransmitted, the grant information representing that connection to theexternal network is granted, and the communication apparatus furthercomprises: a management section configured to register the predeterminedapparatus having transmitted the grant information, as a gateway usedfor the connection to the external network.
 13. The communicationapparatus according to claim 12, wherein the management section selects,on a basis of a connection capability of each predetermined apparatusrepresented by the parameter, the predetermined apparatus requestingconnection to the external network, and the communication controlsection transmits the connection request information to thepredetermined apparatus selected.
 14. The communication apparatusaccording to claim 13, wherein, in a case where the predeterminedapparatus requesting connection to the external network is newlyselected, the communication control section transmits, to thepredetermined apparatus, cancellation request information representing arequest for cancellation of the connection to the external network. 15.The communication apparatus according claim 11, wherein thecommunication control section controls transmission power for radiowaves within a range in which communication with another apparatuswithin a network is enabled.
 16. The communication apparatus accordingto claim 15, wherein the another apparatus within the network includes acontrol apparatus responsible for a function for access control in thewireless LAN.
 17. The communication apparatus according to claim 12,wherein the communication control section performs transmission of datato the predetermined apparatus at a timing overlapping a timing fortransmission, by the another apparatus within the wireless LAN, of datato another of the predetermined apparatuses responsible for the functionof the gateway.
 18. The communication apparatus according to claim 12,wherein the communication control section performs reception of datatransmitted from the predetermined apparatus at a timing overlapping atiming for reception, by the another apparatus, of data transmitted byanother of the predetermined apparatuses responsible for the function ofthe gateway.
 19. A communication system comprising: a firstcommunication apparatus included in a wireless LAN including a pluralityof communication apparatuses functioning as gateways, the firstcommunication apparatus including a communication control sectionconfigured to transmit, when the first communication apparatus isconnected to an external network, a management frame including aparameter related to a capability of connecting to the external network,to another apparatus within the wireless LAN; and a second communicationapparatus operating as the first communication apparatus and including acommunication control section configured to receive the management frametransmitted from the first communication apparatus and transmit, to thefirst communication apparatus, connection request informationrepresenting a request for connection to the external network.